Merge branch 'cb/maint-orphan-merge-noclobber'
[git/kirr.git] / tree-diff.c
blob12c9a88884ec3bb70a1744e44235c578a44e08e6
1 /*
2 * Helper functions for tree diff generation
3 */
4 #include "cache.h"
5 #include "diff.h"
6 #include "diffcore.h"
7 #include "tree.h"
9 static char *malloc_base(const char *base, int baselen, const char *path, int pathlen)
11 char *newbase = xmalloc(baselen + pathlen + 2);
12 memcpy(newbase, base, baselen);
13 memcpy(newbase + baselen, path, pathlen);
14 memcpy(newbase + baselen + pathlen, "/", 2);
15 return newbase;
18 static char *malloc_fullname(const char *base, int baselen, const char *path, int pathlen)
20 char *fullname = xmalloc(baselen + pathlen + 1);
21 memcpy(fullname, base, baselen);
22 memcpy(fullname + baselen, path, pathlen);
23 fullname[baselen + pathlen] = 0;
24 return fullname;
27 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
28 const char *base, int baselen);
30 static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt)
32 unsigned mode1, mode2;
33 const char *path1, *path2;
34 const unsigned char *sha1, *sha2;
35 int cmp, pathlen1, pathlen2;
36 char *fullname;
38 sha1 = tree_entry_extract(t1, &path1, &mode1);
39 sha2 = tree_entry_extract(t2, &path2, &mode2);
41 pathlen1 = tree_entry_len(path1, sha1);
42 pathlen2 = tree_entry_len(path2, sha2);
43 cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
44 if (cmp < 0) {
45 show_entry(opt, "-", t1, base, baselen);
46 return -1;
48 if (cmp > 0) {
49 show_entry(opt, "+", t2, base, baselen);
50 return 1;
52 if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
53 return 0;
56 * If the filemode has changed to/from a directory from/to a regular
57 * file, we need to consider it a remove and an add.
59 if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
60 show_entry(opt, "-", t1, base, baselen);
61 show_entry(opt, "+", t2, base, baselen);
62 return 0;
65 if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
66 int retval;
67 char *newbase = malloc_base(base, baselen, path1, pathlen1);
68 if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
69 newbase[baselen + pathlen1] = 0;
70 opt->change(opt, mode1, mode2,
71 sha1, sha2, newbase, 0, 0);
72 newbase[baselen + pathlen1] = '/';
74 retval = diff_tree_sha1(sha1, sha2, newbase, opt);
75 free(newbase);
76 return retval;
79 fullname = malloc_fullname(base, baselen, path1, pathlen1);
80 opt->change(opt, mode1, mode2, sha1, sha2, fullname, 0, 0);
81 free(fullname);
82 return 0;
86 * Is a tree entry interesting given the pathspec we have?
88 * Pre-condition: baselen == 0 || base[baselen-1] == '/'
90 * Return:
91 * - 2 for "yes, and all subsequent entries will be"
92 * - 1 for yes
93 * - zero for no
94 * - negative for "no, and no subsequent entries will be either"
96 static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
98 const char *path;
99 const unsigned char *sha1;
100 unsigned mode;
101 int i;
102 int pathlen;
103 int never_interesting = -1;
105 if (!opt->nr_paths)
106 return 2;
108 sha1 = tree_entry_extract(desc, &path, &mode);
110 pathlen = tree_entry_len(path, sha1);
112 for (i = 0; i < opt->nr_paths; i++) {
113 const char *match = opt->paths[i];
114 int matchlen = opt->pathlens[i];
115 int m = -1; /* signals that we haven't called strncmp() */
117 if (baselen >= matchlen) {
118 /* If it doesn't match, move along... */
119 if (strncmp(base, match, matchlen))
120 continue;
123 * If the base is a subdirectory of a path which
124 * was specified, all of them are interesting.
126 if (!matchlen ||
127 base[matchlen] == '/' ||
128 match[matchlen - 1] == '/')
129 return 2;
131 /* Just a random prefix match */
132 continue;
135 /* Does the base match? */
136 if (strncmp(base, match, baselen))
137 continue;
139 match += baselen;
140 matchlen -= baselen;
142 if (never_interesting) {
144 * We have not seen any match that sorts later
145 * than the current path.
149 * Does match sort strictly earlier than path
150 * with their common parts?
152 m = strncmp(match, path,
153 (matchlen < pathlen) ? matchlen : pathlen);
154 if (m < 0)
155 continue;
158 * If we come here even once, that means there is at
159 * least one pathspec that would sort equal to or
160 * later than the path we are currently looking at.
161 * In other words, if we have never reached this point
162 * after iterating all pathspecs, it means all
163 * pathspecs are either outside of base, or inside the
164 * base but sorts strictly earlier than the current
165 * one. In either case, they will never match the
166 * subsequent entries. In such a case, we initialized
167 * the variable to -1 and that is what will be
168 * returned, allowing the caller to terminate early.
170 never_interesting = 0;
173 if (pathlen > matchlen)
174 continue;
176 if (matchlen > pathlen) {
177 if (match[pathlen] != '/')
178 continue;
179 if (!S_ISDIR(mode))
180 continue;
183 if (m == -1)
185 * we cheated and did not do strncmp(), so we do
186 * that here.
188 m = strncmp(match, path, pathlen);
191 * If common part matched earlier then it is a hit,
192 * because we rejected the case where path is not a
193 * leading directory and is shorter than match.
195 if (!m)
196 return 1;
198 return never_interesting; /* No matches */
201 /* A whole sub-tree went away or appeared */
202 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
204 int all_interesting = 0;
205 while (desc->size) {
206 int show;
208 if (all_interesting)
209 show = 1;
210 else {
211 show = tree_entry_interesting(desc, base, baselen,
212 opt);
213 if (show == 2)
214 all_interesting = 1;
216 if (show < 0)
217 break;
218 if (show)
219 show_entry(opt, prefix, desc, base, baselen);
220 update_tree_entry(desc);
224 /* A file entry went away or appeared */
225 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
226 const char *base, int baselen)
228 unsigned mode;
229 const char *path;
230 const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
231 int pathlen = tree_entry_len(path, sha1);
233 if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
234 enum object_type type;
235 char *newbase = malloc_base(base, baselen, path, pathlen);
236 struct tree_desc inner;
237 void *tree;
238 unsigned long size;
240 tree = read_sha1_file(sha1, &type, &size);
241 if (!tree || type != OBJ_TREE)
242 die("corrupt tree sha %s", sha1_to_hex(sha1));
244 if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
245 newbase[baselen + pathlen] = 0;
246 opt->add_remove(opt, *prefix, mode, sha1, newbase, 0);
247 newbase[baselen + pathlen] = '/';
250 init_tree_desc(&inner, tree, size);
251 show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
253 free(tree);
254 free(newbase);
255 } else {
256 char *fullname = malloc_fullname(base, baselen, path, pathlen);
257 opt->add_remove(opt, prefix[0], mode, sha1, fullname, 0);
258 free(fullname);
262 static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt, int *all_interesting)
264 while (t->size) {
265 int show = tree_entry_interesting(t, base, baselen, opt);
266 if (show == 2)
267 *all_interesting = 1;
268 if (!show) {
269 update_tree_entry(t);
270 continue;
272 /* Skip it all? */
273 if (show < 0)
274 t->size = 0;
275 return;
279 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
281 int baselen = strlen(base);
282 int all_t1_interesting = 0;
283 int all_t2_interesting = 0;
285 for (;;) {
286 if (DIFF_OPT_TST(opt, QUICK) &&
287 DIFF_OPT_TST(opt, HAS_CHANGES))
288 break;
289 if (opt->nr_paths) {
290 if (!all_t1_interesting)
291 skip_uninteresting(t1, base, baselen, opt,
292 &all_t1_interesting);
293 if (!all_t2_interesting)
294 skip_uninteresting(t2, base, baselen, opt,
295 &all_t2_interesting);
297 if (!t1->size) {
298 if (!t2->size)
299 break;
300 show_entry(opt, "+", t2, base, baselen);
301 update_tree_entry(t2);
302 continue;
304 if (!t2->size) {
305 show_entry(opt, "-", t1, base, baselen);
306 update_tree_entry(t1);
307 continue;
309 switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
310 case -1:
311 update_tree_entry(t1);
312 continue;
313 case 0:
314 update_tree_entry(t1);
315 /* Fallthrough */
316 case 1:
317 update_tree_entry(t2);
318 continue;
320 die("git diff-tree: internal error");
322 return 0;
326 * Does it look like the resulting diff might be due to a rename?
327 * - single entry
328 * - not a valid previous file
330 static inline int diff_might_be_rename(void)
332 return diff_queued_diff.nr == 1 &&
333 !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
336 static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
338 struct diff_options diff_opts;
339 struct diff_queue_struct *q = &diff_queued_diff;
340 struct diff_filepair *choice;
341 const char *paths[1];
342 int i;
344 /* Remove the file creation entry from the diff queue, and remember it */
345 choice = q->queue[0];
346 q->nr = 0;
348 diff_setup(&diff_opts);
349 DIFF_OPT_SET(&diff_opts, RECURSIVE);
350 DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
351 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
352 diff_opts.single_follow = opt->paths[0];
353 diff_opts.break_opt = opt->break_opt;
354 paths[0] = NULL;
355 diff_tree_setup_paths(paths, &diff_opts);
356 if (diff_setup_done(&diff_opts) < 0)
357 die("unable to set up diff options to follow renames");
358 diff_tree(t1, t2, base, &diff_opts);
359 diffcore_std(&diff_opts);
360 diff_tree_release_paths(&diff_opts);
362 /* Go through the new set of filepairing, and see if we find a more interesting one */
363 opt->found_follow = 0;
364 for (i = 0; i < q->nr; i++) {
365 struct diff_filepair *p = q->queue[i];
368 * Found a source? Not only do we use that for the new
369 * diff_queued_diff, we will also use that as the path in
370 * the future!
372 if ((p->status == 'R' || p->status == 'C') && !strcmp(p->two->path, opt->paths[0])) {
373 /* Switch the file-pairs around */
374 q->queue[i] = choice;
375 choice = p;
377 /* Update the path we use from now on.. */
378 diff_tree_release_paths(opt);
379 opt->paths[0] = xstrdup(p->one->path);
380 diff_tree_setup_paths(opt->paths, opt);
383 * The caller expects us to return a set of vanilla
384 * filepairs to let a later call to diffcore_std()
385 * it makes to sort the renames out (among other
386 * things), but we already have found renames
387 * ourselves; signal diffcore_std() not to muck with
388 * rename information.
390 opt->found_follow = 1;
391 break;
396 * Then, discard all the non-relevant file pairs...
398 for (i = 0; i < q->nr; i++) {
399 struct diff_filepair *p = q->queue[i];
400 diff_free_filepair(p);
404 * .. and re-instate the one we want (which might be either the
405 * original one, or the rename/copy we found)
407 q->queue[0] = choice;
408 q->nr = 1;
411 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
413 void *tree1, *tree2;
414 struct tree_desc t1, t2;
415 unsigned long size1, size2;
416 int retval;
418 tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
419 if (!tree1)
420 die("unable to read source tree (%s)", sha1_to_hex(old));
421 tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
422 if (!tree2)
423 die("unable to read destination tree (%s)", sha1_to_hex(new));
424 init_tree_desc(&t1, tree1, size1);
425 init_tree_desc(&t2, tree2, size2);
426 retval = diff_tree(&t1, &t2, base, opt);
427 if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
428 init_tree_desc(&t1, tree1, size1);
429 init_tree_desc(&t2, tree2, size2);
430 try_to_follow_renames(&t1, &t2, base, opt);
432 free(tree1);
433 free(tree2);
434 return retval;
437 int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
439 int retval;
440 void *tree;
441 unsigned long size;
442 struct tree_desc empty, real;
444 tree = read_object_with_reference(new, tree_type, &size, NULL);
445 if (!tree)
446 die("unable to read root tree (%s)", sha1_to_hex(new));
447 init_tree_desc(&real, tree, size);
449 init_tree_desc(&empty, "", 0);
450 retval = diff_tree(&empty, &real, base, opt);
451 free(tree);
452 return retval;
455 static int count_paths(const char **paths)
457 int i = 0;
458 while (*paths++)
459 i++;
460 return i;
463 void diff_tree_release_paths(struct diff_options *opt)
465 free(opt->pathlens);
468 void diff_tree_setup_paths(const char **p, struct diff_options *opt)
470 opt->nr_paths = 0;
471 opt->pathlens = NULL;
472 opt->paths = NULL;
474 if (p) {
475 int i;
477 opt->paths = p;
478 opt->nr_paths = count_paths(p);
479 if (opt->nr_paths == 0) {
480 opt->pathlens = NULL;
481 return;
483 opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
484 for (i=0; i < opt->nr_paths; i++)
485 opt->pathlens[i] = strlen(p[i]);